Hello everyone,
Yesterday, I discovered mold behind a picture in our new semi-detached house (on an exterior wall, insulated with some kind of wool – I don’t know the exact type).
The picture has been hanging in the children’s room for about 14 days, and I am quite shocked and confused.
We moved in three weeks ago.
The construction phase lasted about one year.
Residual moisture in a new build is understandable. Maybe I shouldn’t have hung the picture there (it’s the only one in the house), but the mold seems to have appeared very quickly (diameter of the spot about 10cm (4 inches)).
Our furniture is all placed a few centimeters (inches) away from the walls to allow air circulation and to reduce residual moisture.
We ventilate by briefly opening windows in the morning, evening, and sometimes during the day.
According to the baby monitor in the children’s room, humidity levels range between 65 – 80%.
Our underfloor heating is currently off.
I am now very worried, especially about the area around the fitted kitchen, which is also on an exterior wall.
What would be the best way to proceed?
Should I call a building expert right away to have everything checked?
Is it enough to treat the affected area with ethanol, or should it be sanded down, or is it better to consult a mold specialist?
What are effective preventative measures? Many people say “heat, ventilate, heat, ventilate,” but how does that work with slow-reacting underfloor heating?
Perhaps someone has advice that could help me.
Thank you very much in advance!
C.
Yesterday, I discovered mold behind a picture in our new semi-detached house (on an exterior wall, insulated with some kind of wool – I don’t know the exact type).
The picture has been hanging in the children’s room for about 14 days, and I am quite shocked and confused.
We moved in three weeks ago.
The construction phase lasted about one year.
Residual moisture in a new build is understandable. Maybe I shouldn’t have hung the picture there (it’s the only one in the house), but the mold seems to have appeared very quickly (diameter of the spot about 10cm (4 inches)).
Our furniture is all placed a few centimeters (inches) away from the walls to allow air circulation and to reduce residual moisture.
We ventilate by briefly opening windows in the morning, evening, and sometimes during the day.
According to the baby monitor in the children’s room, humidity levels range between 65 – 80%.
Our underfloor heating is currently off.
I am now very worried, especially about the area around the fitted kitchen, which is also on an exterior wall.
What would be the best way to proceed?
Should I call a building expert right away to have everything checked?
Is it enough to treat the affected area with ethanol, or should it be sanded down, or is it better to consult a mold specialist?
What are effective preventative measures? Many people say “heat, ventilate, heat, ventilate,” but how does that work with slow-reacting underfloor heating?
Perhaps someone has advice that could help me.
Thank you very much in advance!
C.
It sounds like you moved in too early. Did you measure the moisture levels before installing the flooring? An indoor humidity of 80% is quite high, in my opinion.
From my experience with new constructions, after the screed is poured, the house is either dried using dehumidifiers or heated with a special screed drying program on the heating system for 4 to 6 weeks. During this period, you need to visit the house regularly to ventilate and dry the windows. The indoor temperature can reach almost 40°C (104°F). At least, that’s how I know it. Afterward, the residual moisture is measured to decide whether it’s suitable for moving in or for wallpapering and tiling.
I’m not an expert, but I would remove the wallpaper at the affected area to check if the damage is worse. When in doubt, always hire a professional, especially in a child’s room. You might also consider having your build inspected by a certified expert to see if any poor workmanship occurred. It might cost a bit, but it could be worth its weight in gold.
Or wait for someone with more experience to respond. I’m just sharing what I would do...
From my experience with new constructions, after the screed is poured, the house is either dried using dehumidifiers or heated with a special screed drying program on the heating system for 4 to 6 weeks. During this period, you need to visit the house regularly to ventilate and dry the windows. The indoor temperature can reach almost 40°C (104°F). At least, that’s how I know it. Afterward, the residual moisture is measured to decide whether it’s suitable for moving in or for wallpapering and tiling.
I’m not an expert, but I would remove the wallpaper at the affected area to check if the damage is worse. When in doubt, always hire a professional, especially in a child’s room. You might also consider having your build inspected by a certified expert to see if any poor workmanship occurred. It might cost a bit, but it could be worth its weight in gold.
Or wait for someone with more experience to respond. I’m just sharing what I would do...
Hello,
it obviously seems to be a solid wall construction?
Your descriptions sound like insufficient drying of the building.
I also wonder whether, for example, the maximum residual moisture of the subfloor was taken into account when installing the floor coverings (tiles, laminate?).
I have heard that mold growth can occur at relative humidity levels above 70%.
Around 40–60% is generally considered normal.
I would simply start by addressing this with the builder and ventilate, ventilate, ventilate—as long as the outside air is not more humid than the inside (which I believe is usually not a problem unless it’s a basement).
Best regards...
it obviously seems to be a solid wall construction?
Your descriptions sound like insufficient drying of the building.
I also wonder whether, for example, the maximum residual moisture of the subfloor was taken into account when installing the floor coverings (tiles, laminate?).
I have heard that mold growth can occur at relative humidity levels above 70%.
Around 40–60% is generally considered normal.
I would simply start by addressing this with the builder and ventilate, ventilate, ventilate—as long as the outside air is not more humid than the inside (which I believe is usually not a problem unless it’s a basement).
Best regards...
B
Bauexperte19 Jul 2012 17:21Hello,
Did you complete a drying process after the screed was laid? When were the walls wallpapered after the screed was poured, and did you notice any problems during that time?
I assume you have not installed a mechanical ventilation system? Ventilating only twice a day is definitely not enough! 80% relative humidity is clearly too high!
Before I provide suggestions, please respond to my questions first; then we can continue.
Kind regards
Cleaner schrieb:
Hello community,
yesterday I discovered mold behind a picture in our new semi-detached house (exterior wall, insulated with some kind of wool – I don’t have the exact name right now). The picture in the children’s room has been hanging there for about 14 days, and I am quite shocked and confused. We moved in 3 weeks ago.
Construction phase lasted about 1 year.
Did you complete a drying process after the screed was laid? When were the walls wallpapered after the screed was poured, and did you notice any problems during that time?
Cleaner schrieb:
We ventilate by opening windows briefly in the morning, evening, and sometimes in between.
According to the baby monitor in the children’s room, the humidity level is between 65 – 80% relative humidity.
Our underfloor heating is currently not turned on.
I am now very concerned, especially about the built-in kitchen, which is also located along the exterior wall.
How should I best proceed?
I assume you have not installed a mechanical ventilation system? Ventilating only twice a day is definitely not enough! 80% relative humidity is clearly too high!
Before I provide suggestions, please respond to my questions first; then we can continue.
Kind regards
H
Häuslebauer4020 Jul 2012 09:55Hello,
During the construction phase, we experienced mold growth. I also reported about this here in the forum. At that time, I had the construction work stopped and brought in an expert to determine whether it was a defect in the construction or just normal construction moisture. Fortunately, it was the latter. Since it was winter for us, it was relatively easy to remove the moisture by repeatedly airing out the house during the day.
The opinions of the expert and our site manager differed greatly back then. The site manager wanted to continue using drying equipment and fans, while the expert advised to get rid of those and air out the house several times a day. This method is far more effective in cold, dry outdoor temperatures than one or several dehumidifiers, and he was right.
It was important that the house was heated thoroughly before airing out, as warm indoor air holds much more moisture. Then, by opening the windows wide, you could literally watch the hygrometers drop from 75% to below 50%. This way, even during the construction and finishing phase, we managed to keep the indoor humidity at a consistently tolerable level between 50 and 65%.
Of course, this approach makes less sense in summer, especially since outdoor humidity is usually high due to the weather. But maybe you can still take advantage of the slightly cooler evening hours, provided it is dry outside, to air out the house.
This method naturally does not make sense,
During the construction phase, we experienced mold growth. I also reported about this here in the forum. At that time, I had the construction work stopped and brought in an expert to determine whether it was a defect in the construction or just normal construction moisture. Fortunately, it was the latter. Since it was winter for us, it was relatively easy to remove the moisture by repeatedly airing out the house during the day.
The opinions of the expert and our site manager differed greatly back then. The site manager wanted to continue using drying equipment and fans, while the expert advised to get rid of those and air out the house several times a day. This method is far more effective in cold, dry outdoor temperatures than one or several dehumidifiers, and he was right.
It was important that the house was heated thoroughly before airing out, as warm indoor air holds much more moisture. Then, by opening the windows wide, you could literally watch the hygrometers drop from 75% to below 50%. This way, even during the construction and finishing phase, we managed to keep the indoor humidity at a consistently tolerable level between 50 and 65%.
Of course, this approach makes less sense in summer, especially since outdoor humidity is usually high due to the weather. But maybe you can still take advantage of the slightly cooler evening hours, provided it is dry outside, to air out the house.
This method naturally does not make sense,
Thank you for the feedback.
I have already informed the site manager, and the moisture will be measured soon.
The screed dried for about 8 weeks before we started painting/wallpapering. The drying program was also followed.
About 2 weeks before the painting work, I still had a construction dryer running in the kids’ room, among other places. It was removing about 5 liters of water daily at first, and in the end, only about 2 liters.
There were no issues with mold during the construction phase.
Another thought I had concerns the picture itself (it comes from someone who previously had mold in their basement...the picture frame might have been stored there). Could spores from the picture have transferred onto the wall?
I have checked the entire house afterwards and found no damp walls or mold anywhere.
Should I maybe turn on the underfloor heating during the day and then ventilate the room thoroughly in the evening?
Thanks again for your help!!!
I have already informed the site manager, and the moisture will be measured soon.
The screed dried for about 8 weeks before we started painting/wallpapering. The drying program was also followed.
About 2 weeks before the painting work, I still had a construction dryer running in the kids’ room, among other places. It was removing about 5 liters of water daily at first, and in the end, only about 2 liters.
There were no issues with mold during the construction phase.
Another thought I had concerns the picture itself (it comes from someone who previously had mold in their basement...the picture frame might have been stored there). Could spores from the picture have transferred onto the wall?
I have checked the entire house afterwards and found no damp walls or mold anywhere.
Should I maybe turn on the underfloor heating during the day and then ventilate the room thoroughly in the evening?
Thanks again for your help!!!
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